1<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> 2<html> 3 4<head> 5<META http-equiv="Content-Type" content="text/html; charset=windows-1252"> 6<META name="GENERATOR" content="Microsoft FrontPage 5.0"> 7<META http-equiv="Content-Style-Type" content="text/css"> 8<LINK rel="stylesheet" type="text/css" href="../../CSS/revolution.css"> 9<title>GXReadBoundingBox</title> 10</head> 11 12<body> 13 14<h1 align="left">GXReadBoundingBox</h1> 15 16 17<h2>C Specification</h2> 18 19<dl> 20 <dd><PRE><CODE>#include <revolution/gx.h></CODE></PRE></dd> 21 <dd><pre><CODE>void GXReadBoundingBox( 22 u16* left, 23 u16* top, 24 u16* right, 25 u16* bottom );</CODE></pre></dd> 26</dl> 27<h2>Arguments</h2> 28<TABLE border="1" cellpadding="3" cellspacing="0.1"> 29 <tr> 30<TD width="120" bgcolor="#ffffe8"><em><strong><CODE>left</font></strong></em></TD> 31<TD width="520">The leftmost pixel in the bounding box</TD> 32 </tr> 33 <tr> 34<TD width="120" bgcolor="#ffffe8"><em><strong><CODE>top</font></strong></em></TD> 35<TD width="520">The uppermost line in the bounding box</TD> 36 </tr> 37 <tr> 38<TD width="120" bgcolor="#ffffe8"><em><strong><CODE>right</font></strong></em></TD> 39<TD width="520">The rightmost pixel in the bounding box</TD> 40 </tr> 41 <tr> 42<TD width="120" bgcolor="#ffffe8"><em><strong><CODE>bottom</font></strong></em></TD> 43<TD width="520">The lowest line in the bounding box</TD> 44 </tr> 45</TABLE> 46<h2>Return Values</h2> 47 48<p>None.</p> 49<H2>Description</H2> 50<P>The graphics hardware keeps track of a bounding box of pixel coordinates that are drawn in the Embedded Frame Buffer (EFB). These bounding box values can be used to determine the area of the EFB to copy (using <a href="GXSetTexCopySrc.html"><code>GXSetTexCopySrc</code></a>).</P> 51<P>This function reads the bounding box values. <a href="GXClearBoundingBox.html"><code>GXClearBoundingBox</code></a> can be used to reset the values of the bounding box.</P> 52<P>Since hardware can only test the bounding box in quads (2x2 pixel blocks), the result of this function may contain error of plus or minus 1 pixel. Also because of this, <strong><code><b><em>left</em></b></code></strong> and <code><strong><em>top</em></strong></code> are always even-numbered and <code><strong><em>right</em></strong></code> and <code><strong><em>bottom</em></strong></code> are always odd-numbered.</P> 53 54 55 56 57<h2>See Also</h2> 58 59<p><A href="GXClearBoundingBox.html"><CODE>GXClearBoundingBox</CODE></A></p> 60<H2>Revision History</H2> 61<P>2006/03/01 Initial version.</P><hr> 62<P>CONFIDENTIAL</p> 63</BODY> 64</HTML>